Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Sure is a nice piece!
The aging, first outside in all kinds of weather, then the boiling seems to have taken out the tannins, and that is an indication that it has probably also broken down any other products that may be harmful or toxic.
I think I would try it with just a few fish. If there is any hint that they are not doing well (when you know all other issues are taken care of) then assume the wood is the cause, and get them out of that water. Don't use the wood.